Radial compression studies of WS2 nanotubes in the elastic regimea)

Multiwalled nanotubes and nanoparticles of metal dichalcogenides express unique mechanical and tribological characteristics. A widely studied member of this class of materials is the WS2 nanotube whose structure consists of layers of covalent W-S bonds joined by the van der Waals interactions between the sulfur layers which mediate any interlayer sliding or compression. One of the intriguing aspects of these structures is the response of these layers under mechanical stress. Such internal degrees of freedom can profoundly impact on the overall mechanical response. The fact that the internal structure of these nanotubes is well characterized enables a full treatment of the problem. Here, the authors report an experimental and modeling study of the radial mode of deformation. Three independent atomic force microscope experiments were employed to measure the nanomechanical response using both large (radius=100 nm) and small (radius=3–15 nm) probe tips. Two different analytical models were applied to analyze ...